package com.dexcoder.demo.utils;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class SpringContextHolder implements ApplicationContextAware {
    private static ApplicationContext applicationContext;
  
    /** 
     * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量. 
     */  
    public void setApplicationContext(ApplicationContext applicationContext) {  
        SpringContextHolder.applicationContext = applicationContext; // NOSONAR  
    }  
  
    /** 
     * 取得存储在静态变量中的ApplicationContext. 
     */  
    public static ApplicationContext getApplicationContext() {  
        checkApplicationContext();  
        return applicationContext;  
    }  
  
    /** 
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型. 
     */  
    @SuppressWarnings("unchecked")  
    public static <T> T getBean(String name) {  
        checkApplicationContext();  
        return (T) applicationContext.getBean(name);  
    }  
  
    /** 
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型. 
     */  
    public static <T> T getBean(Class<T> clazz) {  
        checkApplicationContext();  
        return applicationContext.getBean(clazz);
    }  
  
    /** 
     * 清除applicationContext静态变量. 
     */  
    public static void cleanApplicationContext() {  
        applicationContext = null;  
    }  
  
    private static void checkApplicationContext() {  
        if (applicationContext == null) {  
            throw new IllegalStateException(  
                    "applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");  
        }  
    }  
}  
